Artículo
The microbial mercury link in oligotrophic lakes: Bioaccumulation by picocyanobacteria in natural gradients of dissolved organic matter
Soto Cárdenas, Estela Carolina
; Queimaliños, Claudia Patricia
; Ribeiro, Sergio; Gerea, Marina
; Dieguez, Maria del Carmen
Fecha de publicación:
09/2019
Editorial:
Pergamon-Elsevier Science Ltd
Revista:
Chemosphere
ISSN:
0045-6535
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Andean Patagonian lakes are oligotrophic systems characterized by low dissolved organic carbon (DOC) levels and moderate to high Hg concentration that determine naturally high Hg/DOC ratios and bioavailability. In these lakes, microbial food webs are extremely important in Hg trophodynamics, being that the picophytoplankton fraction is a major entrance path of Hg2+ into pelagic food webs. This study analyzed the bioaccumulation of Hg2+ by the picocyanobacteria Synechococcus sp. using the radiotracer 197Hg2+ and water from four Andean Patagonian lakes presenting a natural gradient of DOM concentration and quality. Hg2+ bioaccumulation by Synechococcus was calculated as the uptake of Hg2+ per biovolume unit (volume concentration factor VCF; pL μm−3). Hg uptake showed a wide variation (13 < VCF< 300 pL μm−3) in the natural DOC gradient tested (0.7–4 mg L−1; Hg2+/DOC ratio: 1.8–14 ng mg−1). The bioaccumulation of Hg2+ in Synechococcus decreased exponentially with DOC concentration. Differences in the quality of dissolved organic matter (DOM) among lake water influenced also Hg2+ bioaccumulation. Naturally degraded DOM, with low molecular weight/size, promoted higher Hg uptakes in Synechococcus compared to humic DOM, rich in high molecular weight/size aromatic compounds, that retained Hg in the dissolved phase. In Andean Patagonian lakes picocyanobacteria are pivotal organisms in the Hg cycling, taking dissolved Hg2+ and transferring it to pelagic food webs, as well as fueling the benthic Hg pathway through sedimentation.
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(INIBIOMA)
Articulos de INST. DE INVEST.EN BIODIVERSIDAD Y MEDIOAMBIENTE
Articulos de INST. DE INVEST.EN BIODIVERSIDAD Y MEDIOAMBIENTE
Citación
Soto Cárdenas, Estela Carolina; Queimaliños, Claudia Patricia; Ribeiro, Sergio; Gerea, Marina; Dieguez, Maria del Carmen; The microbial mercury link in oligotrophic lakes: Bioaccumulation by picocyanobacteria in natural gradients of dissolved organic matter; Pergamon-Elsevier Science Ltd; Chemosphere; 230; 9-2019; 360-368
Compartir
Altmétricas